Primary teeth in adults--a pilot study.

Remaining primary teeth are occasionally found in adults. The cause and the long-term survival may vary. The aim of this investigation was to study the occurrence and condition of primary teeth in adults in a county in Sweden. All dentists in general practice were asked to send in radiographs showing remaining primary teeth in patients aged 18 years and more. The following variables were registered: 1) age, 2) gender, 3) year of exposure of the radiograph, 4) location of the primary tooth, 5) impaction of the permanent successor, 6) fillings or caries in the primary tooth, 7) amount of root resorption and 8) infraocclusion of the primary tooth. 35 dentists contributed with radiographs from 65 subjects showing 89 retained primary teeth. The most commonly found tooth was the second primary molar in the mandible, followed by the primary canine in the maxilla. Except for maxillary molars, most of the primary teeth showed a moderate degree of root resorption. No relationship was found between the degree of root resorption and gender, fillings/caries or infraocclusion. For the mandibular primary molars, there was a statistically significant correlation between root resorption and age. The mesial root of the molar in the mandible was more affected by root resorption than the distal, and the degree of root resorption of the mesial and distal roots was found to be closely correlated. Also, the results indicated a symmetrical pattern of root resorption in bilateral cases of remaining mandibular second primary molars.